Picture of a high pressure fuel pump on a 2012 F10 N55 engine,,,customer complaints of long crank during start up,,,integrated fault memory,,,no faults,,,,I then performed fuel rail pressure test was ok,,,,performed fuel injector leakage test ok,,,performed fuel pressure holding pressure after shutting off ok.,,,so there are only a couple things that can cause long crank,,,,number 1 the high pressure fuel pump,,,number 2 low fuel pressure sensor,,,,ok 3 things fuel injector bad or leaking,,,,if a fuel injector is bad you would have rough running or fuel coming out the exhaust,,,,and we don’t have that,,,so the problem is fuel pump or low fuel pressure sensor,,,,and there are no faults for the sensor,,,and fuel rail pressure was ok. So we decided to remove the high pressure fuel pump,,,,we have to remove this oil sensor which sits right behind the high pressure fuel pump,,,,you have to remove it to gain access to the rear bolt for the high pressure fuel pum. Here is the small hole in the engine block where the oil sensor is located.,,,,on the old N54 that sensor was not in the way of replacing the fuel pump,,,,,they changed that on the N55. Here is the old and the new fuel pumps,,,there is no change,,,,,this fuel pump is the same in the N54,,,,when the N54 came out we were replacing the high pressure fuel pump everyday,,,the first couple of designs were very bad ,,,,they finally go it right after all these years.
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